Steam iron comprising a scaling indicator

ABSTRACT

The invention concerns a steam iron comprising a scaling indicator ( 10 ) and including a heating element ( 3 ) provided with a vaporizing chamber ( 30 ) for producing steam, the heating element ( 3 ) comprising an electrical heating resistor ( 31 ) controlled by a thermostat ( 6 ). The invention is characterized in that it is equipped with means for counting the number of cycles closing or opening the thermostat ( 6 ) and in that the scaling indicator ( 10 ) is activated based on the number of cycles of the thermostat ( 6 ).

The present invention relates to a household steam iron comprising a heating body provided with a steam chamber and more particularly refers to a household iron having a scale formation indicator making it possible to alert the user to the need for carrying out a maintenance operation.

There is known, from the patent application EP 1 045 932, a steam iron having a scale formation indicator that is activated after a predetermined time of use of the iron, the latter having means allowing to measure the cumulative time of use of the steam iron.

Such a scale formation indicator has the advantage of encouraging the user to regularly carry out an operation of self-cleaning of the iron to evacuate the particles of tartar, or scale, or fur accumulated in the steam chamber.

However, such a method of activation of the scale formation indicator requires a timer to measure the time of use of of the iron and presents the disadvantage of being relatively expensive to implement while not being very representative of the actual state of calcification, or scaling, of the iron.

The invention which follows aims at providing a steam iron provided with a scale formation indicator activated according to a different solution that is simple and economical to produce, and which allows to obtain a better correspondence between the real state of scaling of the iron and the moment of activation of the scale formation indicator.

The goal of the invention is achieved by a steam iron having a scale formation indicator and comprising a heating body containing a steam chamber for the production of steam, the heating body has an electric heating resistance whose operation is controlled by a thermostat, wherein it is furnished with means making it possible to count the number of cycles of closing or opening of the thermostat and the scale formation indicator is activated as a function of the number of cycles of the thermostat.

According to another characteristic of the invention, the iron has a cord for its connection to an electric power mains and means making it possible to count the number of connections or disconnections of the cord to the electric power mains in order to determine the number of ironing sessions and the scale formation indicator is activated as a function of the accumulated number of cycles of the thermostat and the accumulated number of ironing sessions.

According to another characteristic of the invention, the scale formation indicator means is activated when the cumulative number of cycles of the thermostat exceeds a predetermined threshold and the number of ironing sessions is greater than a given value.

According to another characteristic of the invention, the means for counting the number of cycles of closing, or of opening, of the thermostat are integrated into an electronic circuit controlling the activation of the scale formation indicator.

According to another characteristic of the invention, the electronic circuit receives from the thermostat information relating to its closing and/or its opening.

According to another characteristic of the invention, the electronic circuit has a nonvolatile memory storing information relating to the cumulative number of cycles of the thermostat and/or the cumulative number of ironing sessions.

According to another characteristic of the invention, the scale formation indicator is light disposed on the body of the iron.

According to another characteristic of the invention, the threshold of activation of the scale formation indicator is modulated as a function of the degree of hardness the water introduced into the steam chamber, which is indicated by the user.

According to still another characteristic of the invention, the iron comprises a button whose actuation during a predetermined time allows reinitialization of the calculation of the number of cycles of the thermostat.

According to another characteristic of the invention, the button effectuatin reinitialization also constitutes a button for self-cleaning provoking the abrupt arrival of a large quantity of water in the steam chamber.

One will understand better the goals, aspects and advantages of this invention from the description given hereafter of a particular embodiment of the invention, presented as a non-limiting example, while referring to the annexed drawing in which:

FIG. 1 is a diagrammatic view in longitudinal cross section of a steam iron according to one particular embodiment the invention.

Only the elements necessary for an understanding of the invention have been shown.

The iron, represented schematically in FIG. 1, comprises a case 1 disposed above a soleplate 2 provided with holes for the outlet of steam, not shown in the figure. Soleplate 2 is in thermal communication with a heating body 3 having a steam chamber 30 closed conventionally by a plate 4.

Heating body 3 comprises a heating resistance 31 supplied with current by a thermostat 6 in thermal communication with the heating body, thermostat 6 ensuring the temperature control of soleplate 2 around an assigned temperature defined by the user by means of a button 60. The iron is connected to the electrical supply mains by a cord 5.

In a manner known per se, case 1 contains a water reservoir 8 provided with a filling opening 8 a opening at the front face of the iron and has a drip device 9 that provides a passage for water from reservoir 8 towards the steam chamber 30, this device conventionally having an opening whose cross section can be reduced by a needle.

In order to warn the user of the need for carrying out a descaling operation on the iron, the latter comprises a scale formation indicator constituted by a light 10 that is activated by an electronic circuit 11. This electronic circuit 11 is advantageously fed with electricity by the electrical supply mains when cord 5 of the steam iron is connected to the mains.

More particularly according to the invention, electronic circuit 11 is connected to thermostat 6 and receives from the latter information relating to its closing or to its opening.

From this information, electronic circuit 11 counts, for example by means of a microprocessor, the number of cycles of closing, or opening, of thermostat 6 then stores in a memory the cumulative number of cycles of thermostat 6 since the first use of the iron.

In order to retain this data in memory when supply cord 5 is disconnected from the mains, electronic circuit 11 has a nonvolatile memory such as a flash memory or EEPROM. In an alternative, electronic circuit 11 can also have a self-contained power source, such as a battery or a capacitor, to preserve the data in memory when supply cord 5 of the steam iron is disconnected from the mains.

In a first embodiment of the invention, electronic circuit 11 activates light 10, to invite the user to carry out an operation of descaling, when the number of cycles of closing, or opening, of thermostat 6, accumulated during different ironing sessions, reaches a predetermined threshold.

In an advantageous manner, the activation of light 10 occurs in a blinking manner to clearly attract the user's attention.

The user is thus invited to effectuate a descaling operation of the iron by setting for example thermostat 6 to the maximum temperature and by pressing on a self-cleaning button 12 provided on the iron so as to cause, in a manner known per se, an abrupt arrival of water from reservoir 8 towards steam chamber 30 in order to obtain a detachment of the particles of tartar, or scale, and their evacuation through the steam holes of soleplate 2.

In a preferred manner, electronic circuit 11 is connected to self-cleaning button 12 and carries out, during actuation of the self-cleaning button for a predetermined time, a resetting to zero of the memory in which is stored the number of cycles of thermostat 6.

The value of the threshold from which light 10 is activated can, for example, be obtained experimentally by causing the iron to operate with full steam with fairly hard water and by measuring the threshold from which the state of scaling of the iron requires a descaling operation.

In an improved alternative, scale formation indicator light 10 is activated when the number of cycles of closing of thermostat 6 exceeds a predetermined threshold and the number of ironing sessions carried out is greater than a given value. It is thus necessary that these two conditions be verified in order for the light to be activated. This permits activation of the light to be prevented after only a few ironing sessions in the case, for example, where the user has left the iron on its heel for a long time, without using it, so that the thermostat was able to have a large number of closing cycles in a relatively short time.

As an example, the scale formation indicator light is activated when the number of connections measured is greater than a threshold X=18 connections and the number of cycles of the thermostat is higher than a threshold Y=1200 cycles. In an advantageous manner, these thresholds of activation X, Y of the scale formation indicator light are modulated in time so that the activation of the scale formation indicator is occurs at relatively long intervals when the iron is new then at increasingly shorter intervals when the iron becomes older and thus more furred.

Thus, for example, during the first two activations of the scale formation indicator, the thresholds of activations will be X=18 and Y=1200, then during the twenty following activations X=10 and Y=750, and finally during the following activations X=5 and Y=360.

In a preferential way, once the scale formation indicator 10 is activated, electronic circuit 11 carries out automatically, during the following connection of cord 5 to the electrical supply mains, a resetting to zero of the memories in which are stored the number of cycles of thermostat 6 and the number of ironing sessions.

In an advantageous manner, the iron can also comprise means making it possible for the user to indicate the degree of hardness of the water introduced into the reservoir, so that the water hardness can be taken into account by the electronic circuit 11 to adapt the activation threshold of scale formation indicator light 10 as a function of the water hardness.

Such an iron in which the scale formation indicator is activated starting from a predetermined number of cycles of closing or opening of the thermostat and number of the number of ironing sessions has the advantage of being simple and economical to produce and of allowing obtaining a good correlation between the moment when the scale formation indicator light is activated and the real state of scaling of the iron. In particular, when the iron is furred, heat exchange between the body and the steam chamber is degraded and the thermostat tends to cycle more quickly what leads to a rapid activation of the scale formation light.

Of course, the invention is by no means limited to the embodiment described and illustrated, which has been given only as an example. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without leaving for all that the field of protection of inventions.

Thus, in an alternative embodiment of the invention, the mechanical thermostat of the iron could be replaced by an electronic thermostat connected to temperature sensors. 

1. Steam iron including a scale formation indicator (10) and comprising a heating body (3) containing a steam chamber (30) for the production of steam, the heating body (3) having an electric heating resistance (31) whose operation is controlled by a thermostat (6), wherein it is provided with means permitting the counting of the number of cycles of closing or opening of the thermostat (6) and the scale formation indicator (10) is activated as a function of the number of cycles of thermostat (6).
 2. Iron according to claim 1, wherein it has a cord (5) for its connection to an electrical supply mains and means making it possible to count the number of connections or disconnections of the cord (5) to the electrical supply mains in order to determine the number of ironing sessions and the scale formation indicator (10) is activated as a function of the cumulative number of cycles of the thermostat (6) and of the number of cumulative ironing sessions.
 3. Iron according to claim 2, wherein the scale formation indicator is activated when the cumulative number of cycles of the thermostat (6) exceeds a predetermined threshold and the number of ironing sessions is greater than a given value.
 4. Iron according to claim 3, wherein said means for counting the number of cycles of closing, or opening, of the thermostat are integrated into an electronic circuit (11) controlling the activation of the scale formation indicator (10).
 5. Iron according to claim 4, wherein said electronic circuit (11) receives from the thermostat information relating to its closing and/or its opening.
 6. Iron according to claim 4, wherein the electronic circuit (11) has a nonvolatile memory in which is stored information relating to the cumulative number of cycles of the thermostat (6) and/or the cumulative number of ironing sessions.
 7. Iron according to claim 1, wherein said scale formation indicator (10) is a light disposed on the body of the iron.
 8. Steam iron according to claim 3, wherein the threshold of activation of the scale formation indicator (10) is modulated as a function of the degree of hardness of the water introduced into the steam chamber (30) which is indicated by the user.
 9. Steam iron according to claim 1, wherein it comprises a button (12) whose actuation for a predetermined time allows reinitialization of the calculation of the number of cycles of the thermostat.
 10. Steam iron according to claim 9, wherein said button effectuating reinitializing also constitutes a button (12) for self-cleaning causing the abrupt arrival of a large quantity of water into the steam chamber. 